Sleeping devices are well known and are employed by a wide variety of users. Such devices generally are configured as having an elongated inner volume for accepting and accommodating the torso of a user. Such sleeping bag devices include warmth-retaining sidewalls surrounding an inner volume having a head opening which can also serve as a means to enter and exit the sleeping bag device.
The body section of the sleeping bag device is provided with a warmth-retaining sidewall of heat-insulating material such as goose down, cotton or synthetic insulation which fills a space between inner and outer lining materials. The outer lining material is oftentimes made waterproof as such products are generally designed to enable a user to lie directly upon the ground which, depending upon climactic conditions, can be wet.
Although traditional sleeping bag devices tend to work adequately to insulate a user outdoors while asleep, the sizing of such products has proven to be somewhat of a challenge. Although most sleeping bag devices are of standard length to accommodate the height of an average user, it is the width of the sleeping bag which provides its internal volume that is addressed in the practice of the present invention. Specifically, gaps are formed between a user's body and the sidewalls of the device. As the user lies within the sleeping bag device, it would be ideal to provide the smallest such gap possible in order to maximize warmth-retaining efficiency. For example, U.S. Pat. No. 4,888,828 issued on Dec. 26, 1989, provides for a means of reducing this gap by providing elastic members which compress the body retaining bag in such a manner as to reduce the cross-sectional area of its inner volume thus allowing the bag to closely fit around the user's body.
In light of the above-noted constraints, it has been found necessary to produce and thus inventory sleeping bag devices of varying widths to accommodate not only single users of various sizes but also to accommodate multiple users in a single bag. For example, a husband and wife may wish to share a single bag rather than to employ two bags, side by side. However, such a bag would be inappropriate for a single user for the internal volume of such a device would be so excessive that heat retention would be most inefficient. Similarly, a bag sized to accommodate a large framed man would be inefficient for use by a small framed woman.
It is thus an object of the present invention to provide a sleeping bag device which can be configured to readily and conveniently change its internal volume to appropriately conform to the torso of its user or users.
It is a further object of the present invention to produce a single sleeping bag device whose internal volume can be readily changed in order to reduce the number of such devices in inventory to accommodate the varying needs of its users.
These and further objects will be more readily appreciated when considering the following drawings and appended claims.